What Species Rules Earth? The Answer May Surprise You

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In the newly released film, "Dawn of the Planet of the Apes,"
humans and apes vie for dominance after a virus has made apes
hyperintelligent while wiping out most humans.

But though apes riding horses, reading and writing in English,
and hunting like Stone Age humans is probably far-fetched, the
idea of another species or life form dominating the planet isn't,
scientists say. In fact, depending on how dominance is defined,
other creatures may already be in charge, experts say. [ The
5 Smartest Non-Primates on the Planet ]

Tough competition

With humans around, it's very difficult for another
superintelligent species to evolve, said Jan Zalasiewicz, a
paleobiologist at the University of Leicester.

"Humans have been quite good at removing the competition,"
Zalasiewicz told Live Science.

Over several million years of evolution, modern humans have
already outcompeted several primates and other human species,
such as Denisovans, hobbitlike creatures dubbed Homo
floresiensis, and
Neanderthals, he said.

Still, the movie's premise isn't too realistic. Apes are unlikely
to supplant us, given that gorillas
and chimpanzees are already struggling in the wild, with slightly
more than 100,000 gorillas worldwide and less than 250,000
chimpanzees worldwide, according to the World Wildlife Fund. (No
other primate populations exceed 100,000.) With 7 billion humans
on the planet, even if 95 percent of them perished as a result of
an engineered virus, the remainder would still greatly outnumber
the apes.

But assuming humans had managed to kill themselves off with
famine, plague, war or climate change, it could take many
millions of years for a new species to evolve the intelligence
and abilities to dominate the Earth. After all, creatures as
intelligent as humans only evolved once in the nearly 3.5 billion
years of life on the planet, Zalasiewicz said.

Rats, ubiquitous pests that live on virtually every scrap of land
on the planet, are already intelligent and have a highly evolved
social structure. In many millions of years, oversized
rats could become a hyperintelligent species that could rule
the Earth. Pigs, too, have complex social structures and a high
level of intelligence, Zalasiewicz said. If they evolved an
ability to use tools and continued to evolve intelligence over
millions of years, they could conceivably take over the planet,
he said.

"If something else intelligent arises, it will be electronic and
[we'll have] made it," Zalasiewicz said.

Researchers recently reported that a machine had passed the
Turing Test, exhibiting behavior that could pass as "human." (In
the Turing Test, if a human interviewer cannot tell the
difference between responses from a machine and a human, then the
machine is said to show intelligent behavior.) And futurist Ray
Kurzweil has long predicted that the singularity, a hypothetical
point
when machine intelligence overtakes human smarts, will be
here by 2045.

Hidden rulers

On some level, humans don't dominate the Earth now.

Bacteria beat out humans in many ways, said Robert J. Sternberg,
a professor of human development at Cornell University in Ithaca,
New York.

"Humans only imagine they dominate the Earth. Bacteria dominate
the Earth," Sternberg wrote in an email to Live Science. "There
are infinitely more of them — well, almost — than there are of
us. Much of our own weight is bacterial. They reproduce faster
and they mutate faster. They have been around far longer than we
have been and they will be around after we are gone."

And bacteria aren't the only contenders for world
domination.

"Ants already control the planet," said Mark W. Moffett, an
entomologist at the Smithsonian Institution in Washington, D.C.,
and author of "Adventures Among Ants: A Global Safari with a Cast
of Trillions" (University of California Press, 2011). "They just
do it under our feet."

For instance, there are many more ants than there are humans, and
their total weight, or biomass, equals or exceeds that of humans,
Moffett said.

They also use traditional military rules of engagement to wage
war. For instance, they rely on "shock and awe," in essence
swarming their enemies with sheer numbers to overcome them. Ants
also throw the weakest, scrawniest members of the colony out
front while keeping their
"supersoldier" ants to the rear, just as the front lines in
many battles are made up of the least trained and most poorly
equipped soldiers, Moffett said.

This strategy has proven incredibly successful.

For instance, individual African army ants may not be scary on
their own, but they create swarms that are 100 feet (30.5 meters)
long and millions-strong. With their little bladelike teeth, they
can swarm and devour a tethered cow — or potentially an
unattended human baby — in minutes, he said.

"There is a reason why women in equatorial Africa carry babies on
their back and don't put them in a crib," Moffett told Live
Science.

The
Argentine Ant first hitched a train ride to California in
1910. Now, a supercolony stretches across most of California, and
is waging all-out war to expand its turf with another supercolony
in Mexico, he said.

And while any one ant isn't all that intelligent, they can still
solve extraordinary problems with their hive mind, Moffett said.

"Individual ants are the equivalent to the neurons in your brain
— each one doesn't have a lot to say but in combination they can
get a lot of things done," Moffett said.